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// MIT License
// Copyright (c) 2019 Erin Catto
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.
#ifndef B2_CHAIN_SHAPE_H
#define B2_CHAIN_SHAPE_H
#include "b2_api.h"
#include "b2_shape.h"
class b2EdgeShape;
/// A chain shape is a free form sequence of line segments.
/// The chain has one-sided collision, with the surface normal pointing to the right of the edge.
/// This provides a counter-clockwise winding like the polygon shape.
/// Connectivity information is used to create smooth collisions.
/// @warning the chain will not collide properly if there are self-intersections.
class B2_API b2ChainShape : public b2Shape
{
public:
b2ChainShape();
/// The destructor frees the vertices using b2Free.
~b2ChainShape();
/// Clear all data.
void Clear();
/// Create a loop. This automatically adjusts connectivity.
/// @param vertices an array of vertices, these are copied
/// @param count the vertex count
void CreateLoop(const b2Vec2* vertices, int32 count);
/// Create a chain with ghost vertices to connect multiple chains together.
/// @param vertices an array of vertices, these are copied
/// @param count the vertex count
/// @param prevVertex previous vertex from chain that connects to the start
/// @param nextVertex next vertex from chain that connects to the end
void CreateChain(const b2Vec2* vertices, int32 count,
const b2Vec2& prevVertex, const b2Vec2& nextVertex);
/// Implement b2Shape. Vertices are cloned using b2Alloc.
b2Shape* Clone(b2BlockAllocator* allocator) const override;
/// @see b2Shape::GetChildCount
int32 GetChildCount() const override;
/// Get a child edge.
void GetChildEdge(b2EdgeShape* edge, int32 index) const;
/// This always return false.
/// @see b2Shape::TestPoint
bool TestPoint(const b2Transform& transform, const b2Vec2& p) const override;
/// Implement b2Shape.
bool RayCast(b2RayCastOutput* output, const b2RayCastInput& input,
const b2Transform& transform, int32 childIndex) const override;
/// @see b2Shape::ComputeAABB
void ComputeAABB(b2AABB* aabb, const b2Transform& transform, int32 childIndex) const override;
/// Chains have zero mass.
/// @see b2Shape::ComputeMass
void ComputeMass(b2MassData* massData, float density) const override;
/// The vertices. Owned by this class.
b2Vec2* m_vertices;
/// The vertex count.
int32 m_count;
b2Vec2 m_prevVertex, m_nextVertex;
};
inline b2ChainShape::b2ChainShape()
{
m_type = e_chain;
m_radius = b2_polygonRadius;
m_vertices = nullptr;
m_count = 0;
}
#endif
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